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Copyright © 2009, David P. Martin, Naval Architect
Westlawn graduate David Martin has spent a lifetime de-
signing all types of boats. His new book,
The Book of Dave
Marin Designs
, is available on CD from Amazon.com.
The
Masthead
will feature excerpts from this fascinating new
work over the next few issues.
55 Ft. Ocean Yachts
Efficiency Under Power
Back in 1968, I began dreaming of a practical seagoing
pleasure boat that would have the efficiency of a hydro-
plane. The Westlawn speed graph showed that a hydroplane
would go 38 M.P.H. at 30 Lbs. per H.P., while a fast vee-
bottom boat would only do 32 M.P.H. at the same 30 Lbs.
per H.P. Arno Apel was a frequent visitor to my offices both
at Atlantic City and at Pacemaker. In fact, at the time he
worked for Pacemaker and was in charge of international
sales, Arno had noticed my preoccupation with the West-
lawn speed charts. One morning he walked into my Pace-
maker office and handed me a speed and power graph pre-
pared by professor George Crouch of Webb Institute of Naval
Architecture. Crouch’s chart showed plots of a few practical
seagoing planing hulls that had already exceeded hydro-
plane efficiency as stated on the Westlawn Speed charts.
Arno had made his mark on the chart with
My Sin
, a three
point hydroplane at about 106 M.P.H. Arno’s greatest ac-
complishment, Sir Malcolm Campbell’s
Blue Bird,
at 141
M.P.H., did not fit on the chart. The boat that intrigued me
the most on the chart
was the 55 Ft. British
C.M.B. shown.
Crouch’s chart also
appears in the story
about the 47 Ft. Pace-
maker.
The C.M.B., by U.S.
government report,
made 43.4 M.P.H. for
two hours at 34 Lbs.
per H.P., well over
both the Westlawn
Hydroplane Curve and
the Crouch Hydroplane
Curve. There it was,
documented by a
Webb professor and
the U.S. government.
Proof that what I was
striving to do was not only possible, but was already acco
plished by a British genius in 1914.
The C.M.B. was a torpedo boat carrying two stern torpedo
operating in the English Channel. At night, these boats
would cross the channel, make a U-turn in front of the Ge
man U-boat pens, and fire torpedoes out the stern. Germ
anti-aircraft guns were firing skyward at what they thoug
were the airplanes that fired the torpedoes. The British
C.M.B. probably had the longest production run of any bo
in world history, having been in production from 1914 to
1939 when orders were filled for the Chinese Navy.
With information that proved that it was possible to desi
seagoing boat that could equal or exceed hydroplane effi
ciency, I decided to try to do it. All sorts of model configur
tions were designed and built, many hydroplane models
tested. They were
more efficient at h
speeds but at reali
cruising speeds th
had more resistan
than my existing d
signs. Bob O’Donn
and I towed the m
els from an outbo
boat. We towed tw
models at a time
from a yoke. One
model was of an e
isting design abou
which we had real
world performanc
figures. The other
model was a new
experimental desi
The boats were to
at scale speeds usi
55 Ft Ocean
Length Overall .................55’ 8-1/2”
Length Waterline ............50’
Beam ................................16’ 4”
Draft ..................................4’ 3”
Displacement ...................59,000 Lbs.
Boating
Magazine Test
Displacement ..................58,000 Lbs. Normal Full Load
Fuel Capacity ...................1,000 Gal.
Water Capacity ...............200 Gal.
55 Ft Ocean Particulars